The invention relates to a heat-sealable paperboard laminate structure for use as a container of various food products. More particularly, this invention relates to a laminate structure for use in a container or the like containing an outer non-food contact layer of a biodegradable polymeric material. Coating one side of the package with a biodegradable resin increases the amount of surface area that is accessible to microbial action.
Heat-sealable paperboard containers comprised of various laminate structures are widely used in the container industry. A growing concern regarding the solid-waste disposal of containers coated on two sides with non-degradable polymers has arisen, and a solution to the non-readily biodegradable container has been widely sought.
One solution to the industry wide problem is to produce a container comprised of 100% recyclable high density polyethylene. This solution is problematical for reuse in the same packaging application due to the strict FDA standards which prevent use of recycled products for food contact. More problematical are blended laminate plastic structures, which are not recyclable due to the inability to effectively separate the various blended layers during recycling. All plastic containers are essentially non-biodegradable, also.
If incineration of the plastic container is attempted to minimize the amount of solid waste, environmental problems are encountered due to the release of heavy metal catalysts into the atmosphere.
Essentially, 100% plastic containers create enormous solid-waste disposal problems and a number of State governments have enacted legislation to ban or tax the use of plastic packages or containers.
An alternative solution to the industry wide problem is to utilize "one-side" paperboard structures which comprise 90-95% paperboard and which biodegrade at a rapid rate over time.
These containers possess deficiencies in that they are coated only on one side by layers of polymer resins to prevent leakage and spoilage of the food product contained therein, and not on both sides causing poor mechanical integrity with large size containers, leakage, and ineffective seams.
It is an object of this invention to produce a paperboard-based packaging material that possesses superior barrier and container properties as well as the ability to substantially biodegrade at a rapid rate over time.
It is an object of this invention to produce a paperboard-based packaging material that is coated on its exterior non-food product contact side with a biodegradable thermoplastic material and on its interior food contact side with a selected barrier resin material.
It is an object of this invention to produce a novel paperboard-based packaging material which meets and in some cases exceeds the degradability standards being imposed by State legislatures.
To date, there have been no commercially available paperboard-based or 100% plastic resin structure which produces a package which will biodegrade at a rapid rate and be structurally strong enough to hold food products in an acceptable manner.